Polyamide substrates, such as nylon carpeting, upholstery fabric and the like, are subject to staining by a variety of agents, e.g., foods and beverages. An especially troublesome staining agent is FD&C Red Dye No. 40, commonly found in soft drink preparations. Different types of treatments have been proposed to deal with staining problems. One approach is to apply a highly fluorinated polymer to the substrate. Another is to use a composition containing a sulfonated phenol-formaldehyde condensation product.
For example, Liss et al., in U.S. Pat. No. 4,963,409, disclose stain-resistant synthetic polyamide textile substrates having deposited on them sulfonated phenol-formaldehyde polymeric condensation products. However, sulfonated phenol-formaldehyde condensation products are themselves subject to discoloration; commonly they turn yellow. Yellowing problems are described by W. H. Hemmpel in a Mar. 19, 1982 article in America's Textiles, entitled Reversible Yellowing Not Finisher's Fault. Hemmpel attributes yellowing to exposure of a phenol-based finish to nitrogen oxides and/or ultraviolet radiation. To deal with the yellowing problem, the condensation products were modified by Liss et al. by acylation or etherification of some of the phenolic hydroxyls. In a preferred embodiment disclosed by Liss et al., the modified condensation products were dissolved in a hydroxy-containing solvent, such as ethylene glycol prior to there being applied to the textile substrate.
Allen et al., in U.S. Pat. No. 3,835,071, disclose rug shampoo compositions which upon drying leave very brittle, non-tacky residues which are easily removed when dry. The compositions comprise water-soluble metal, ammonium or amine salt of a styrene-maleic anhydride copolymer, or its half ester, and a detergent. Water-soluble metal salts of Group II and the alkali metals (particularly magnesium and sodium) are preferred and ammonium salts are most preferred by Allen et al.
On the other hand, Fitzgerald et al., in U.S. patent application Ser. No. 07/502,819, filed Apr. 2, 1990, now U.S. Pat. No. 5,001,004 disclose the usefulness of aqueous solutions of hydrolyzed vinylaromatic/maleic anhydride copolymers in the treatment of textiles to render them resistant to staining. The preferred copolymer of Fitzgerald et al. is a hydrolyzed styrene/maleic anhydride copolymer. Fitzgerald et al. disclose that the monoalkyl ester of their maleic anhydride/vinyl aromatic polymer was ineffective as a stain-resist. Moreover, hydrolyzed maleic anhydride/alpha-olefin polymer stain-resists (a hydrolyzed maleic anhydride/isobutylene polymer being preferred) are disclosed in my copending U.S. patent application Ser. No. 07/809,843 filed Dec. 18, 1991 which is a continuation-in-part of application Ser. No. 07/626,885 filed Dec. 13, 1990.
Polymers formed from maleic anhydride vinyl- or allyl-ethers are known. See for example: Ind. & Eng. Chem. 41, 1509 (1949) Seymour et.al. "Copolymers of vinyl compounds and maleic anhydride"; J. Phys. Chem. 74, 2842 (1970) Dubin et.al. "Hydrophobic bonding in alternating copolymers of maleic acid and alkyl vinyl ethers"; Europ. Polym. J., 6, 247-58 (1970), Wojtczak et.al., "Etude de la morphologie de copolymers . . . "; Polym. Prepr., ACS, Div. Polym. Chem., 12(1), 445-8 (1971), Wasley et.al., "Copolymers of fluoroalkyl ethers and maleic anhydride"; Charged React. Polym., 2 (Polyelectrolytes their Appl.), 3-13(1975), Dubin et.al., "Hypercoiling in hydrophobic polyacids"; J. Natl. Sci. Counc. Sri Lanka, 7(1), 45-55 (1979), Fujimori et.al., "The alternating copolymerization of n-butyl vinyl ether with maleic anhydride"; Brit. Pat. 1,117,515 "Maleic anhydride-alkyl vinyl ether copolymers"; DE Pat. 2208020 " Fluoroalkyl ether/maleic anhydride copolymers for finishing textiles." (The anhydride copolymer is claimed as soil release agent for wool, cotton and/or polyester textiles from solution in organic solvents); U.S. Pat. No. 4,029,867 "Terpolymers of fluoroalkyl ethers and maleic anhydride".